Premium Charcoal Filters for PetSafe Drinkwell Fountains - 10 PackThese Premium Charcoal filters provide clean, fresh water to your pet. Water is drawn trough the charcoal filter, which is segmented into 6 compartments to facilitate filtration and reduce the settling of the charcoal within the filter. The duo-density pad on each filter captures hair and debris and the charcoal remove odors and eliminates bad taste. These filters are 100% compatible with the following Drinkwell Brand Pet Fountain models: ? Drinkwell Original? Drinkwell Platinium? Drinkwell Big Dog? Drinkwell Multi-Tier? Drinkwell Outdoor Dog? Drinkwell MiniDrinkwell Zen Directions for use: Thoroughly rinse out filter with running water before inserting in to the fountain. Although completely harmless, doing this will cleanse the filter of any charcoal dust that may have become loose.Insert the filter in to your pet fountain. The flow of water should enter through the polyester side and out of the charcoal side which is dark in color. Filter positions will vary by the model of the fountain. The user guide included with your fountain will give specific instructions depending on the model of your fountain. It is recommended the filter be replaced every 2 to 4 week and more frequently if multiple pets are using the fountain.